Abstract: By utilizing Davies form ulations on ion str engthen calibration,the chemical stability constants of fluorine ion pairs obtained under laboratory conditions are corrected in the ion streng then equal to the salinity of 35‰.A iteration computation method has been employed to calculate the chemical forms of fluorineion pairs:free fluorine ion makes up of 49.9%,MgF⁺ 46.8%,and the others are CaF⁺ and NaF⁰.